Ovarian reserve in young women with low birth weight and normal puberty: a pilot case-control study

Association of birth weight, childhood obesity, and age at menarche with the risk of ovarian dysfunction: A mendelian randomization study

BACKGROUND

Observational studies have revealed associations between birth weight, childhood obesity, age at menarche, and ovarian dysfunction. However, these studies are susceptible to unavoidable confounding factors, leading to ongoing debates regarding their conclusions and making causal relationships challenging to infer. In light of these challenges, Mendelian randomization was employed in this study to investigate the causal relationships between birth weight, childhood obesity, age at menarche, and ovarian dysfunction.

METHODS

This study employed a two-sample Mendelian randomization approach using genetic variation as instrumental variables to investigate causal relationships. Genetic variation data were sourced from summary data of genome-wide association studies in European populations. Instrumental variables were selected based on the principles of Mendel's three assumptions. The study utilized the inverse variance weighted method to assess the relationships between birth weight, childhood obesity, age at menarche, and ovarian dysfunction. Supplementary analyses were conducted using MR-Egger regression, the weighted median method, and the weighted median mode to complement the IVW results. Furthermore, the study conducted heterogeneity, horizontal pleiotropy, and sensitivity analyses to evaluate the robustness of the results.

RESULTS

Based on the inverse variance weighted method, it was found that there exists a causal relationship between childhood obesity (OR = 1.378, 95% CI: 1.113∼1.705, p = 0.003), age at menarche (OR = 0.639, 95% CI: 0.468∼0.871, p = 0.005), and ovarian dysfunction, while no causal relationship was observed between birth weight and ovarian dysfunction. Heterogeneity tests, multiplicity tests, and leave-one-out sensitivity analyses did not detect any heterogeneity or multiplicity effects in the estimated impact of these three exposure factors on the risk of ovarian dysfunction.

CONCLUSIONS

This study represents the first evidence suggesting a potential causal relationship between childhood obesity, age at menarche, and ovarian dysfunction. Childhood obesity was found to increase the risk of ovarian dysfunction, while a later age at menarche was associated with a reduced risk of ovarian dysfunction.

Early-life factors and adult anti-Müllerian hormone levels

AIM

This study aims to examine whether early-life factors are associated with adult ovarian reserve, measured by anti-Müllerian hormone (AMH) levels.

METHODS

The work is based on the Jerusalem Perinatal Study (JPS), an extensive birth cohort with detailed information on all pregnancies and deliveries in Jerusalem between 1974 and 1976. A subset of individuals participated in a follow-up study that took place between 2007 and 2009 in which they completed questionnaires and were physically examined at mean age of 32. A blood sample was additionally drawn from each participant, and AMH was measured in a sample of 239 women. The associations between each early-life factors, including birth weight, maternal pre-pregnancy weight, gestational weight gain (GWG), socioeconomic position at birth, and parental smoking during pregnancy, were assessed with AMH levels at the age of 32.Multivariable regression models were used to examine the associations with AMH, adjusting for potential confounders at birth and at the age of 32.

RESULTS

Low birth weight was significantly associated with lower ovarian reserve reflected by lower levels of AMH at age 32 (range 30-36), independent of other early-life factors and after adjusting for confounders (β = 0.180, p = 0.03).

CONCLUSIONS

This prospective study demonstrates the association of birth weight and adult ovarian reserve. Underlying mechanisms are yet to be fully understood.

Sex Hormones, Gonad Size, and Metabolic Profile in Adolescent Girls Born Small for Gestational Age with Catch-up Growth

STUDY OBJECTIVE

To characterize and compare sex hormone concentrations, and uterine and ovarian volumes in adolescent girls born small for gestational age (SGA) who had experienced catch-up growth and girls born at a size appropriate for gestational age (AGA), and to investigate the association between these parameters and glucose metabolism, perinatal factors, and early growth.

DESIGN

A prospective, longitudinal, observational study from birth until adolescence.

SETTING

Mean age at final assessment was 12.7 ± 0.1 years.

PARTICIPANTS

We followed 55 girls (20 SGA, 35 AGA).

INTERVENTIONS AND MAIN OUTCOME MEASURES

Sex hormone concentrations (gonadotropins, estradiol, testosterone, and sex hormone binding globulin) were analyzed, and the oral glucose tolerance test conducted. Uterine and ovarian sizes were assessed using pelvic ultrasound.

RESULTS

Uterine and ovarian volumes were smaller in SGA-born compared with AGA-born girls (P = .013 and P = .039, respectively). SGA girls had lower sex hormone binding globulin levels (P = .039) and higher testosterone levels (P = .003), free androgen index (P < .001), and glycemia 2 hours post glucose load (P = .005) compared with AGA-born girls. Birth weight and early infancy height velocity explained 37.4% of variation in ovarian volume (P = .004), and body mass index at birth, increase in peripheral skinfold thickness during second year of life, and early childhood height velocity explained 43.2% of variation in testosterone levels in adolescence (P = .006).

CONCLUSION

SGA-born girls who experienced catch-up growth remain at risk of biochemical hyperandrogenism in adolescence, and have reduced uterine and ovarian volumes, which might influence future reproductive function. Ovarian size and androgen levels in adolescence might be influenced by early growth and subcutaneous fat deposition.

Nutritional adversity, sex and reproduction: 30 years of DOHaD and what have we learned?

It is well established that early life environmental signals, including nutrition, set the stage for long-term health and disease risk - effects that span multiple generations. This relationship begins early, in the periconceptional period and extends into embryonic, fetal and early infant phases of life. Now known as the Developmental Origins of Health and Disease (DOHaD), this concept describes the adaptations that a developing organism makes in response to early life cues, resulting in adjustments in homeostatic systems that may prove maladaptive in postnatal life, leading to an increased risk of chronic disease and/or the inheritance of risk factors across generations. Reproductive maturation and function is similarly influenced by early life events. This should not be surprising, since primordial germ cells are established early in life and thus vulnerable to early life adversity. A multitude of 'modifying' cues inducing developmental adaptations have been identified that result in changes in reproductive development and impairments in reproductive function. Many types of nutritional challenges including caloric restriction, macronutrient excess and micronutrient insufficiencies have been shown to induce early life adaptations that produce long-term reproductive dysfunction. Many pathways have been suggested to underpin these associations, including epigenetic reprogramming of germ cells. While the mechanisms still remain to be fully investigated, it is clear that a lifecourse approach to understanding lifetime reproductive function is necessary. Furthermore, investigations of the impacts of early life adversity must be extended to include the paternal environment, especially in epidemiological and clinical studies of offspring reproductive function.

Intrauterine, Infant, and Childhood Factors and Ovarian Reserve in Young African American Women

Background: Ovarian toxic exposures during early development may contribute to reduced ovarian reserve in adulthood. Materials and Methods: We explored a range of intrauterine, infant, and childhood factors in relation to a biomarker of ovarian reserve, anti-Müllerian hormone (AMH) concentrations, in adulthood. We conducted a cross-sectional exploratory study of 1600 African American women 23-35 years of age residing in the Detroit, Michigan metropolitan area, who had serum AMH measurements (Ansh Labs PicoAMH enzyme-linked immunosorbent assay) and no previous polycystic ovarian syndrome diagnosis. Information on 32 intrauterine, infant, and childhood factors was ascertained by self-administered questionnaires, with 87% of participants receiving assistance from mothers. The percent differences in AMH concentrations in relation to early-life factors and 95% confidence intervals (CIs) were estimated using multivariable linear regression, adjusting for age, current hormonal contraceptive use, and body mass index. Results: Of the early-life factors evaluated in this study, two maternal pregnancy factors were associated with lower AMH concentrations in adult participants. Participants whose mothers lived or worked on a farm (vs. neither lived nor worked on a farm) when pregnant with the participant had 42% lower AMH concentrations (95% CI = -62 to -9). Among participants whose mothers lived in Michigan when pregnant with the participant (n = 1238), maternal residence in Detroit for at least a month was associated with 22% lower AMH concentrations (95% CI = -34 to -8) in the participant. Conclusions: Further research is merited to replicate our findings and identify the aspects of maternal farm exposure and Detroit residence that may be associated with lower AMH concentrations.

Early-life nutritional effects on the female reproductive system

There is now considerable epidemiological and experimental evidence indicating that early-life environmental conditions, including nutrition, affect subsequent development in later life. These conditions induce highly integrated responses in endocrine-related homeostasis, resulting in persistent changes in the developmental trajectory producing an altered adult phenotype. Early-life events trigger processes that prepare the individual for particular circumstances that are anticipated in the postnatal environment. However, where the intrauterine and postnatal environments differ markedly, such modifications to the developmental trajectory may prove maladaptive in later life. Reproductive maturation and function are similarly influenced by early-life events. This should not be surprising, because the primordial follicle pool is established early in life and is thus vulnerable to early-life events. Results of clinical and experimental studies have indicated that early-life adversity is associated with a decline in ovarian follicular reserve, changes in ovulation rates, and altered age at onset of puberty. However, the underlying mechanisms regulating the relationship between the early-life developmental environment and postnatal reproductive development and function are unclear. This review examines the evidence linking early-life nutrition and effects on the female reproductive system, bringing together clinical observations in humans and experimental data from targeted animal models.

Prenatal exposures and anti-Mullerian hormone in female adolescents: the Avon Longitudinal Study of Parents and Children

Given that the primordial ovarian follicular pool is established in utero, it may be influenced by parental characteristics and the intrauterine environment. Anti-Müllerian hormone (AMH) levels are increasingly recognized as a biomarker of ovarian reserve in females in adulthood and adolescence. We examined and compared associations of maternal and paternal prenatal exposures with AMH levels in adolescent (mean age, 15.4 years) female offspring (n = 1,399) using data from the Avon Longitudinal Study of Parents and Children, a United Kingdom birth cohort study that originated in 1991 and is still ongoing (data are from 1991–2008). The median AMH level was 3.67 ng/mL (interquartile range: 2.46–5.57). Paternal but not maternal smoking prior to and during pregnancy were inversely associated with AMH levels. No or irregular maternal menstrual cycles before pregnancy were associated with higher AMH levels in daughter during adolescence. High maternal gestational weight gain (top fifth versus the rest of the distribution) was associated with lower AMH levels in daughters. Parental age, body mass index, and alcohol intake during pregnancy, child's birth weight, and maternal parity and time to conception were not associated with daughters' AMH levels. Our results suggest that some parental preconceptual characteristics and environmental exposures while the child is in utero may influence the long-term ovarian development and function in female offspring.

Reproductive medicine and inheritance of infertility by offspring: the role of fetal programming

OBJECTIVE

To summarize the molecular processes involved in fetal programming, to describe how assisted reproduction technologies (ART) may affect the epigenetic pattern of the embryo, and to highlight the current knowledge of the role of perinatal events in the subsequent development of reproductive pathology affecting infertile patients.

DESIGN

A literature review of fetal programming of adulthood gynecologic diseases and ART. A Medline search was performed with the following keywords: (fetal programming OR epigenetics OR methylation OR acetylation) AND (IVF OR ART) AND (gynecology). Articles up to October 2010 were selected. Articles and recent reviews were classified by human and animals studies and also according to their experimental or observational design.

SETTING

University hospital research center.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

None.

RESULT(S)

Data from experimental animal models and case-control studies support the potential effect of ART in changing methylation patterns in gametes and embryos. However, these findings are not supported by population studies or experimental studies performed in human gametes/embryos. Experimental and epidemiologic studies support the hypothesis that some adult gynecologic diseases causing infertility may have a fetal origin.

CONCLUSION(S)

Although it seems clear that some adult gynecologic diseases causing infertility may have a fetal origin, there is insufficient evidence to confirm that ART is the origin of later onset, adulthood diseases. Further research in this field must be conducted.